Alaskaman
03-15-2002, 08:39 AM
I'm confused. The 1977 factory service manual indicates that a new style of head was introduced on the L6 engines (FSJ's only, not CJ's) for 1977. It is called the "quench head" which replaced the "wedge head" and came with the 2-bbl BBD carb replacing the 1-bbl. The new design is the "C" code engine. The manual points out that pistons, cam, and head are not interchangable across the change. It also says that the temp sensor is up front on the old style, and on left rear on the new style. Here's the rub, I have the "C" code engine and 2-bbl carb as the book says I should. However, the temp sensor is on the front, which it should not be. I'm getting ready to do a ring and valve, and possibly convert to a 4.0 ltr head so I need to know what I have, preferably before I tear it down. Can any of you 258 guru's shed some light on this for me? Also regarding the 4.0 liter head conversion, will the 4.0 head work on either version of the 258, or is piston change necessary for one or the other? Also, what do the smog nazi's have to say about the 4.0 liter head on a 258?